In recent years, small-scale utility grid systems called microgrid systems have been gathering attention. In a microgrid system, generator devices, which are energy resources, and customers (such as factories, schools, houses, and shops), who consume power, are connected to each other by a utility grid, which is different from any commercial utility grid.
A microgrid system controls power supply according to demand so as to make maximum use of the resources in the system, thereby attempting to provide stable and inexpensive power supply. For example, power consumed by the customers in a system is supplied as much as possible by the power generators in the system, and only insufficient power is bought from an ordinary commercial utility grid, whereby stable and inexpensive power supply is made possible.
Examples of power generators often employed in microgrid systems are those using renewable energy, such as sunlight, wind power, and biomass energy. Power supply from such a power generator is unstable in some cases.
To address this, PTL1 (Japanese Laid-open Patent No. 2012-055087) discloses a technique for controlling distribution of power from power supply sources to power consumption sources in a predetermined area on the basis of information such as environmental variation in power consumption by each of the power consumption sources and power supply by each of the power supply sources. With this technique, it is possible to provide stable power supply by controlling distribution of power from the power supply sources to the power consumption sources on the basis of information such as environmental variation.
Further, PTL2 (Japanese Laid-open Patent No. 2013-110799) discloses a technique for providing an energy storage device, such as a storage battery, in a microgrid system. This technique attempts stable power supply by storing, in the storage battery, power output by a power generator (solar panel) in the microgrid system, and supplying the power stored in the storage battery to customers as needed.